Influenza is a contagious respiratory illness caused by influenza viruses. Antigenic shift and drift lead to new viral strains and seasonal flu. Transmission occurs via droplets, direct contact, or surfaces. Vaccination and good hygiene are recommended for prevention. Antiviral drugs can reduce symptoms but are best taken within 48 hours of symptoms. High risk groups like young children, elderly, and pregnant women should get the flu shot annually.

1. CONTROL AND PREVENTION OF
INFLUENZA

2. Influenza is a contagious respiratory
illness caused by influenza virus.
Worldwide seasonal influenza kills
2,50,000 -5,00,000 people each year.
 antigenic shift & drift properties of
influenza virus are responsible for
emergence of new viral pathogens &
normal flu seasons.

3.  ANTIGENIC SHIFT :two or
more different strains of virus
combine to form a new
subtype,with a mixture of
surface antigens of the two or
more original strains.
 ANTIGENIC DRIFT : small
mutations in hemagglutinin
& neuraminidase genes that
make protein unrecognizable
to pre-existing host
immunity.This leads to
continous process of genetic
& antigenic changes among
flu strains.

4.  Influenza transmission is by 3 ways :
1. Direct transmission into the mucous
membrane of a person .
2. Airborne route – that is via droplets
.(0.5-5 microm diameter)
3. Contaminated surfaces, handles
etc…

6. CONTROL OF INFLUENZA

7. INFECTION CONTROL
 Infection control includes :
Good personal health &
hygiene.
Frequent handwashing
with water & soap or
alcohol ( effective sanitizer
against influenza )
Covering cough and
sneezes.
Avoiding close contact
with infected persons.

8. ANTIVIRAL DRUGS
 Lessens symptoms.
 Prevents flu related complications like pneumonia,
bronchitis, sinus infections,ear infections.
 Two antiviral drugs:
a. Oseltamivir( brand name- tamiflu) : form of
pills/tablets
b. Zanemivir (brand name – relenza) : form of inhaled
powder.
Given for a duration of 5 days.

9. PREVENTION OF INFLUENZA

10.  Influenza vaccines based on concept of herd immunity. .ie,
80% population should be immune to a disease.
 There are two flu seasons annually , corresponding to
occurrence of winter in opposite months in northern &
southern hemisphere.
 Annual reformulation of flu vaccine : each yr 3 influenza
strains(trivalent) that will be most common during
upcoming season are incorporated. This is based on
research by WHO s “Global influenza surveillance
network”.
 Upcoming seasonal flu vaccines contain H1N1, H3N2 and
influenza B strains.

11. vaccination
 Two types of vaccines are
available:
a. Flu shots
b. Nasal spray flu vaccine
(LAIV – live attenuated
influenza vaccine )
DNA based vaccines are in
clinical trial.

12.  FLU SHOT:
o Inactivated vaccine (
containing killed virus)
o Approved for > 6 months old,
including healthy people &
people with chronic medical
conditions.
o 3 different types :
i. Regular dose for 6 months
and older
ii. High dose > 65yrs
iii. Intermediate flu shot (18-
64 yrs.)

13.  NASAL SPRAY FLU VACCINES :
Live weakened flu viruses.
LAIV
Healthy people ( 2-49 yrs)

14.  People at high risk of
developing flu related
complications are
potential candidates of
influenza vaccine.
1. Children < 5yrs ;
especially < 2 yrs
2. Older people >65 yrs.
3. Pregnant women

15. 4. Medical conditions like
 Asthma, heart disease
 Blood disorders like sickle cell anaemia
 Liver disorders , kidney disorders
 Endocrine disorders like diabetes mellitus.
 Metabolic disorders ( inherited metabolic disorders or
mitochondrial isorders)
 Immunocompromised states – HIV/AIDS; prolonged
steroid therapy; malignancies.
 Morbidly obese (BMI > 40)
 Long term aspirin therapy.

16. Side effects of vaccine
 INJECTIONS:
Mild soreness,redness and swelling at the injection site.
Fever
Aches
Guillian barre syndrome (rare)
• NASAL SPRAY :
 Nasal congestion, running nose
 Cough, wheezing
 Fever
 Headache, myalgia
 Allergic reaction
 Abdominal pain ( more so in children )

17.  CONTRAINDICATIONS :
I. Severe reaction to influenza vaccination in <6
months.
II. Severe allergy to chicken eggs that is used to grow
the virus strains.
III. Moderate to severe illness with fever.
IV. History of Guillian barre syndrome.

18. WHO RECOMMENDATIONS
 Get yourself & your
family members (> 6
months of age )
vaccinated against
current strains of
influenza.
 Keep distance from
people with symptoms
of influenza like illness,
coughing & sneezing

19.  Clean hands thoroughly with
soap & water/ alcohol based
hand rub on regular basis.
 Avoid touching your mouth ,
nose , eyes as much as
possible.
 Reduce time spent in
crowded places.
 Improve airflow in our living
spaces by opening windows.
 Practice good health habits
(adequate sleep, nutritious
food ,keeping physically
active).

20. CDC RECOMMENDATIONS
 Cover nose & mouth with
tissue when coughing /
sneezing.
 Wash hands with soap &
water especially after
coughing &
sneezing.alcohol based
cleansers are also effective.
 Avoid touching eyes
,mouth, nose to avoid
spread of germs.

21.  Try to avoid close contact
with sick people.
 Those sick with flu like
illness should stay at
home until fever has
subsided > 24 hrs.